Honda CBF 125 smoking.

moley101 · L Plate Warrior Joined: 05 Feb 2013 Karma :

Hi Im new to this forum, after being away from bikes for the last 15 years and being my last bike was a Suzuki GP125 I have recently brought and 2009 honda cbf 125 privately.
Just wondering if anyone has any ideas, the bike runs really well no idling issues and will do 65 mph ok, but at low rpm while riding (normally pulling away) the bike smokes and burns a little oil.
now I was used to an old 2 stroke needing and burning oil but did not expect this to be the case with a 4 stroke.
The bike itself like i say runs well no rattle type noises and pulls as i would expect a 125 to do.
Any help or ideas would grateful.

Thanks Again All.

lukamon · World Chat Champion Joined: 18 May 2007 Karma :

whats the milage?
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killa wrote: Im an ass man myself

moley101 · L Plate Warrior Joined: 05 Feb 2013 Karma :

13000 miles mot done in november no issue on that and serviced by a local motorcycle shop 300 miles ago with a report on smoking but recommendation adjusting valves, done this but with no improvement.

lukamon · World Chat Champion Joined: 18 May 2007 Karma :

reeks of being thrashed / siezed. i'd take the head off and put some new rings on the piston Thumbs Up

edit: out of interest, what condition? how much?
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killa wrote: Im an ass man myself

toshpot · Scooby Slapper Joined: 12 Aug 2012 Karma :

I'm no pro, by any stretch of the imagination, but have you checked your oil? has it been overfilled at all?

I've come across oil in the airbox before, due to overfilling.
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evoboy · World Chat Champion Joined: 20 Aug 2009 Karma :

Scored barrel.

Been ran low on oil.

Would'nt be the first one.
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Suzuki GT250 x7------- Fazer 600------CB250RS------Aprilia Rally 70----- Bandit 600

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uberkron · Crazy Courier Joined: 12 Nov 2012 Karma :

gp125, awesome introduction to bikes. I had one, the fun ended when I had to hold it in fifth gear.

As for your four smoker, normally the head holds oil longer than the bore so take out the plug and shine a torch in there.
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i ride a zip 50 2smoke. It overtakes a hundred times a day.

Rogerborg · nimbA Joined: 26 Oct 2010 Karma :

unitynotsocri... · Banned Joined: 29 Jun 2011 Karma :

you could redo the barrel n piston,new valve guides n seals and head overhaul.
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nearly a normal tax paying tosser.......with ferrileness suzi100,cg125,cb125scb100n,cb175,cd100,cj250t,kh250,c15,125 bantam,super 6,rickman gs750,xt500,250rs,dt175,lifan125,dolomite1850,metro,Morris220ld,morrisfg,leyland princess,range rover,corsa,vw camper .now struggling with legs. MORE ORDER = MORE CHAOS

stevo as b4 · World Chat Champion Joined: 17 Jul 2003 Karma :

if it sounds ok, and is doing 65mph, then i'd be checking the oil every other day, and topping up as required. If it's not using too much oil i'd say 0.5l per 500-600miles, then id just leave it well alone and top it up.

you'll be changing the oil anyway every 1000miles, and cleaning the strainer gauze out if you've got sense and mechanical sympathy that is.

Other than that just ride it and ride it hard, you should get 30'000+ miles out of a Honda 125 before needing to do any engine work, and some have done alot more, it's down to maintainence and frequent oil changes.

Rogerborg · nimbA Joined: 26 Oct 2010 Karma :

stevo as b4 · World Chat Champion Joined: 17 Jul 2003 Karma :

I take it that it's about 1/10th as robust as a Brazilian CG125 then?

The CG and XLR125's are where most of my 4stroke 125 experiences come from. My mate's 91J CG was up to 38'000 when it finally chewed up a LHS main bearing. It still ran though, and i think he forgot the 1000mile oil change rule about 3-4times in a row, so it was a sturdy enough motor in my mind.

neil. · World Chat Champion Joined: 24 Feb 2008 Karma :

You really must check the oil strainer behind the clutch cover as these love to clog up with clutch friction material fluff amongst all else, starving the top end of oil. I'd say I top up around 50ml every 600-ish miles, been that way since very early on in the bike's life. Just ticked over 21'500 miles. These CBFs are a really poor successor to the CG. You can't run the engine on sludge, in fact you need to service it to the letter and the rust issues some people have had are terrible. Then there's the fuel pump kangaroo issue. You can tell they're built to a price. I still like mine though, it's cheap and easy to work on and fantastic on fuel at 130mpg.
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CBT February 2008 | A2 June 2008 | Yamaha YBR125 (written off) | Honda CBF125 (current)

lukamon · World Chat Champion Joined: 18 May 2007 Karma :

how often do you guys clean the centri oil filter? mine is just under a year old and about to roll over 5k. changed the oil every 1k from the start Smile

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killa wrote: Im an ass man myself

neil. · World Chat Champion Joined: 24 Feb 2008 Karma :

Never, judging by reports it doesn't get significantly dirty (a bit of sludge that will fit on the end of your thumb) and the screws on mine are bastard tight so I gave up trying. The strainer is the one to watch - first time I did mine at 7.5k it was filthy. No harm in checking it earlier and if you're lucky with the screws, no harm in checking the centrifugal filter but I don't think it's worth it unless you're rebuilding a shagged engine where swarf etc will have been circulating around it.
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CBT February 2008 | A2 June 2008 | Yamaha YBR125 (written off) | Honda CBF125 (current)

mudcow007 · World Chat Champion Joined: 01 Feb 2012 Karma :

the centrifugal on my CG was covered in sludge when i got it - an the screws looked brand new so it doesn't look like its ever been touched...in nearly 30 years?!

lukamon · World Chat Champion Joined: 18 May 2007 Karma :

cool. might do the screen on mine at the weekend, i'm going to have to order a RHS crankcase gasket right?
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killa wrote: Im an ass man myself

neil. · World Chat Champion Joined: 24 Feb 2008 Karma :

Yes and a gasket for the centrifugal filter if you decide to do it too.
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CBT February 2008 | A2 June 2008 | Yamaha YBR125 (written off) | Honda CBF125 (current)

moley101 · L Plate Warrior Joined: 05 Feb 2013 Karma :

Hi all thanks for all the responces.
A local bike shop has had the bike apart and an oil seal at the bottom of the piston was twisted, rings and bore marked due low compression as a result.
They will be putting back together tomorrow so hope to be back on the road by the weekend.

Thanks to the guys at SAS Custom Bikes.

lukamon · World Chat Champion Joined: 18 May 2007 Karma :

sounds good Smile

how much are they charging you?

i cleaned the strainer on mine. it was fair covered in crap at 5k. couldnt get the spinner cover off though.
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killa wrote: Im an ass man myself

unitynotsocri... · Banned Joined: 29 Jun 2011 Karma :

reccomend you always check the strainer and use a m,agnet when deopping the oil.Cg oil drops on new engines,under 1,000miles,usually contain bit of spare metal from rough edges and its perfectly normal.OHC engines are a litle different.OIL MUST BE CLEAn,otherwise the cam knacks in no time.OHC centrifugal oil pumps differ from pushrods,rather than oil gunge ,OHC engines have a nice mixture of gunge and powderd ally.

Dont think centrifugal filter on the pump really needs doing ,reccomend you only bother if you need to change the clutch plates.
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nearly a normal tax paying tosser.......with ferrileness suzi100,cg125,cb125scb100n,cb175,cd100,cj250t,kh250,c15,125 bantam,super 6,rickman gs750,xt500,250rs,dt175,lifan125,dolomite1850,metro,Morris220ld,morrisfg,leyland princess,range rover,corsa,vw camper .now struggling with legs. MORE ORDER = MORE CHAOS